Here's how a digital camera works: you point it at the thing and press the thing and the picture comes on the thing at the back. That's basically all you need to know, except for one thing: more megapixels are not necessarily better. The new Fujifilm F200 EXR, announced today alongside the budget A150 and A100, features a clever new sensor that attempts to prove less is more.

The F200 packs a 1/1.6-inch Super CCD EXR sensor, which is the doohickey inside that captures light. The new technology is designed to adjust the way the camera deals with light depending on the conditions. When light comes into the camera through the lens, it falls on the image sensor, which translates the light into information and thus creates the digital image. The surface of the sensor is covered in tiny light-collecting maguffins called photodiodes, the number of which is measured in megapixels.

The F200 has 12 million of these photodiodes, making it a 12-megapixel sensor. That's more than enough for producing large, detailed pictures, so Fujifilm has hit on the idea of modifying how many pixels are used in different conditions. The EXR sensor allows you to double up each pixel, cutting total resolution to 6 megapixels, but increasing the amount of light each pixel will capture. This is designed to work in low light conditions, when smaller pixels usually struggle, resulting in grainy noise. You can also choose to double up pixels in a way that will capture greater detail when there's a lot of contrast in your shot: for example, a skyline with a light sky against a dark horizon.

The camera can pick one of these three options itself, or leave it up to you. Clever stuff -- we're looking forward to trying it out. The F200 also includes a 76mm (3-inch) LCD screen, 5x optical zoom and optical image stabilisation. Face Detection 3.0 finds faces and adjusts shooting settings accordingly, with a 28mm wide-angle lens fitting plenty in.

At the budget end of proceedings, enter the A150 and A100. They're separated-at-birth similar, featuring 10-megapixels, 3x zoom, 14 scene modes and powered by AA batteries. They'll be available this month, but we'll have to wait and see about pricing. Click on our photos to see more of the new models.